Speed humps have no benefit at all.
Resources can be saved if speed humps are not built.

Humans are vulnerable so collision by a car at 20 kmph hardly makes any difference with 40 kmph.
Madmen will drive recklessly regardless of speed humps or child pedestrians.
Watch out for the cars instead.

In Malaysia, speed humps and potholes are too abundant that they can be considered specialties of this country.
A few speed humps are commonly found on a short stretch of road.

Failure modes of speed humps

When a car slows down for the speed bump, another car from behind may not slow down on time and causes rear-end collision.

Speed humps can send a fast car airborne and then down with a crash.

Some pedestrians may presume that speed humps will slow down cars but this is not always the case.
The car can speed over the hump or accelerate after the hump.
The presumption can be dangerous.
Pedestrians should be trained to pay full attention to approaching vehicles.

At night when vehicles climb a speed hump, headlights point up and may dazzle drivers coming from the front.